U.S. patent application number 10/400801 was filed with the patent office on 2003-10-09 for reservoir unit.
Invention is credited to Suzuki, Nobuo, Toki, Tomonari.
Application Number | 20030188786 10/400801 |
Document ID | / |
Family ID | 28449883 |
Filed Date | 2003-10-09 |
United States Patent
Application |
20030188786 |
Kind Code |
A1 |
Toki, Tomonari ; et
al. |
October 9, 2003 |
Reservoir unit
Abstract
A reservoir unit to be installed within a fuel tank, in order to
prevent bubbles generated by the fuel transfer jet pump of the fuel
tank from feeding into the internal combustion engine, comprising a
wall formed in a closed bag shape so that the delivered flow of
fuel can fully turn round the discharge port of a jet pump, against
which fuel containing bubbles delivered from the jet pump hits and,
after turning around a partition wall a plurality of times, fills
the reservoir unit, with the result that bubbles can be removed
from the fuel more efficiently and the fuel in the reservoir can be
prevented from containing a large quantity of bubbles.
Inventors: |
Toki, Tomonari; (Ohbu,
JP) ; Suzuki, Nobuo; (Ohbu, JP) |
Correspondence
Address: |
STEVENS, DAVIS, MILLER & MOSHER, L.L.P.
Suite 850
1615 L Street, N.W.
Washington
DC
20036
US
|
Family ID: |
28449883 |
Appl. No.: |
10/400801 |
Filed: |
March 28, 2003 |
Current U.S.
Class: |
137/565.34 |
Current CPC
Class: |
B01D 35/26 20130101;
F02M 37/46 20190101; B01D 36/001 20130101; F02M 37/50 20190101;
Y10T 137/86043 20150401; F02M 37/025 20130101; F02M 37/106
20130101; B01D 35/30 20130101; F02M 37/20 20130101; B01D 2201/4084
20130101; B01D 35/0273 20130101; B01D 2201/208 20130101 |
Class at
Publication: |
137/565.34 |
International
Class: |
F02M 037/14 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 3, 2002 |
JP |
2002-101248 |
Claims
What is claimed is:
1. A reservoir unit having an anti-bubble device comprising: a
cylindrical reservoir having a bottom installed in a fuel tank, a
fuel pump for sucking fuel in that reservoir, a pressure regulator
for regulating pressure of the fuel delivered from the fuel pump at
a constant level by allowing part of the fuel delivered from that
fuel pump to escape, a jet pump for accepting that fuel escaping
from the pressure regulator, generating a negative pressure by
utilizing its flow velocity, and introducing fuel outside the
reservoir into the reservoir with that negative pressure, and a
wall which is located near the discharge port of that jet pump and
against which the flow of fuel delivered from the jet pump
hits.
2. A reservoir unit as claimed in claim 1, wherein said wall
surrounds the discharge port of the jet pump and its height is
lower than that of the side wall of the reservoir.
3. A reservoir unit as claimed in claim 2, wherein a partition wall
is formed at a central part in said full-circle wall and the flow
delivered by the jet pump turns round the partition wall.
4. A reservoir unit as claimed in claim 3, wherein clearances are
secured between two sides of said partition wall and the
full-circle wall, and the flow delivered from the jet pump can flow
fully round the partition wall.
5. A reservoir unit as claimed in claim 1, wherein said wall and
reservoir are integrally molded of resin.
6. A reservoir unit as claimed in claim 2, wherein said wall and
reservoir are integrally molded of resin.
7. A reservoir unit as claimed in claim 3, wherein said wall and
reservoir are integrally molded of resin.
8. A reservoir unit as claimed in claim 4, wherein said wall and
reservoir are integrally molded of resin.
9. A reservoir unit as claimed in claim 1, wherein said fuel tank
is made of resin.
10. A reservoir unit as claim in claim 2, wherein said fuel tank is
made of resin.
11. A reservoir unit as claim in claim 3, wherein said fuel tank is
made of resin.
12. A reservoir unit as claim in claim 4, wherein said fuel tank is
made of resin.
13. A reservoir unit as claim in claim 5, wherein said fuel tank is
made of resin.
14. A reservoir unit as claim in claim 6, wherein said fuel tank is
made of resin.
15. A reservoir unit as claim in claim 7, wherein said fuel tank is
made of resin.
16. A reservoir unit as claim in claim 8, wherein said fuel tank is
made of resin.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a fuel supply equipment
which can be suitably used in supplying fuel in a fuel tank of a
motor vehicle to its engine or the like. More particularly, it
relates to a reservoir unit comprising a reservoir which is
installed in a fuel tank to prevent the fuel pump from racing when
the remaining volume of fuel in the tank has become very small and
a jet pump for introducing fuel outside that reservoir into the
reservoir.
[0003] 2. Description of the Related Art
[0004] A conventional fuel tank for motor vehicles or the like uses
a fuel supply equipment comprising a sub-tank formed in the fuel
tank, a fuel pump for sucking fuel in the sub-tank, a pressure
regulator for regulating the pressure of the fuel discharged from
the fuel pump by allowing part of the fuel discharged by the fuel
pump to escape, and a jet pump, fixed to a wall of the sub-tank,
for receiving the fuel escaping from the pressure regulator,
utilizing the flow velocity of the escaping fuel to generate a
negative pressure and using that negative pressure to introduce the
fuel outside the sub-tank into the sub-tank.
[0005] This fuel supply equipment causes the fuel in the sub-tank
to be fed to the vehicle engine or the like by the fuel pump. The
pressure of fuel fed to the vehicle engine or the like is kept
constant by the pressure regulator. Whereas keeping the pressure
constant requires letting any excess volume of fuel escape, the
energy that the escaping fuel has is utilized to introduce the fuel
outside the sub-tank into the sub-tank. With this fuel supply
equipment, even if the fuel in the fuel tank decreases and its
surface level drops, the fuel level in the sub-tank is kept high,
thereby enabling the last drop of fuel in the fuel tank to be
effectively used.
[0006] When the fuel outside the sub-tank is introduced into the
sub-tank with the jet pump, bubbles are apt to be introduced into
the sub-tank. According to the related art, a large enough capacity
of the sub-tank is secured not to allow bubbles to spread
throughout the inside space of the sub-tank.
[0007] It is difficult to form a sub-tank in a resin-built fuel
tank, which is coming into extensive use. In view of this
difficulty, instead of forming a sub-tank, a structure in which a
cylindrical reservoir having a bottom is installed in the fuel tank
is beginning to be adopted. In this case, the reservoir is reduced
in size with a corresponding limitation on its capacity. As a
result, bubbles in the fuel fed by a jet pump into the reservoir
tend to spread throughout the inside of the reservoir. If bubbles
pervade throughout the inside of the reservoir, various problems
will arise, such as vapor locking of the fuel pump and the failure
of the intended quantity of fuel to reach the engine or the like
due to the presence of bubbles in the fuel.
SUMMARY OF THE INVENTION
[0008] An object of the present invention, created in view of the
problems noted above, is to extinguish the bubbles which would
otherwise accompany the introduction of fuel outside a reservoir
into the reservoir by a jet pump to be introduced into the
reservoir and thereby to prevent the presence of a large quantity
of bubbles in the fuel contained in the reservoir.
[0009] The invention makes use of the finding that, by causing the
flow of bubble-containing fuel discharged from the jet pump to hit
a wall, the fuel in the reservoir (at least the part of the fuel
near the bottom of the reservoir where the sucking action of the
fuel pump works) can be prevented from letting a large quantity of
bubbles being present therein.
[0010] According to the invention, there is provided a reservoir
unit having an anti-bubble device, comprising a cylindrical
reservoir having a bottom installed in a fuel tank; a fuel pump for
sucking fuel in that reservoir: a pressure regulator for regulating
the pressure of the fuel delivered from the fuel pump at a constant
level by allowing part of the fuel delivered from that fuel pump to
escape; a jet pump for receiving that fuel escaping from the
pressure regulator, generating a negative pressure by utilizing its
flow velocity, and introducing fuel outside the reservoir into the
reservoir with that negative pressure; and a wall which is located
near the discharge port of that jet pump and against which the flow
of fuel delivered from the jet pump hits. The reservoir in this
context is a vessel for fuel storage installed in the fuel
tank.
[0011] With this reservoir unit having an anti-bubble device, fuel
containing bubbles delivered from the jet pump fills the reservoir
after it hits against the wall. Causing the fuel containing bubbles
to hit the wall, thereby to be cleared of bubbles and to fill the
reservoir enables the fuel effectively cleared of bubbles to fill
the reservoir, and resulting in prevention of allowing a large
quantity of bubbles to be introduced into the fuel in the tank.
[0012] In the invention, the wall may surround the discharge port
of the jet pump and its height may be lower than that of the side
wall of the reservoir.
[0013] With the wall fully surrounding the discharge port of the
jet pump, the fuel can be cleared of bubbles contained in it when
introduced from the jet pump before the bubbles dissipate in the
reservoir. As the wall surrounding the discharge port is closed
like a bag, the fuel present in the reservoir outside the
full-circle wall remains in the reservoir even if the fuel pump
stops and the fuel within the reservoir goes out of the reservoir
through the jet pump. The full-circle wall forbids the fuel near
the suction port of the fuel pump from going out of the
reservoir.
[0014] In the structure described above, it is also possible to
form a partition wall on the central part in the full-circle wall
and cause the flow delivered by the jet pump to turn round the
partition wall.
[0015] With this configuration, the fuel delivered from the jet
pump fills the reservoir after the flow delivered from the jet pump
has turned round the partition wall, and bubbles are removed from
the fuel in the reservoir even more efficiently.
[0016] In this structure, it is further possible to provide
clearances between both sides of the partition wall and the
full-circle wall, and to enable the flow delivered from the jet
pump to flow fully round the partition wall.
[0017] With this configuration, the fuel delivered from the jet
pump fills the reservoir after the flow delivered from the jet pump
has turned round the partition wall a plurality of times, and
bubbles are removed from the fuel in the reservoir even more
efficiently.
[0018] In the invention, the reservoir and the anti-bubble wall may
be integrally molded of resin.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a schematic side view of a whole reservoir unit
according to the present invention.
[0020] FIG. 2A is a plan view of a reservoir according to a first
preferred embodiment of the invention, and FIG. 2B is a sectional
view taken along a center line (line IIB-IIB) of a jet pump in FIG.
2A.
[0021] FIGS. 3A through 3C are front views of one example and its
modified versions of a partition wall according to the first
embodiment of the invention.
[0022] FIG. 4A is a sectional view of a primary filter, and FIG. 4B
is a plan view of the same.
[0023] FIG. 5A is a front view of an upper subunit, and FIG. 5B is
a side view of the same.
[0024] FIG. 6 is a perspective view showing how guide rails and a
sheath-shaped slot engage with each other.
[0025] FIG. 7 is a plan view of a reservoir according to a second
preferred embodiment of the invention.
[0026] FIG. 8 is a plan view of a reservoir according to a third
preferred embodiment of the invention.
[0027] FIG. 9 is a plan view of a reservoir according to a fourth
preferred embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] The following paragraphs enumerate principal features of the
preferred embodiments according to the present invention to be
described below.
[0029] (Mode 1) The reservoir is molded of resin, and a jet pump
fitting part and a wall against which the discharge flow from the
jet pump hits are integrally formed with that molded body.
[0030] (Mode 2) The reservoir is pressed toward the bottom of the
fuel tank, and the opening of the jet pump toward outside the
reservoir opens into a minute gap between the bottom of the
reservoir and that of the fuel tank.
[0031] (Mode 3) The reservoir is substantially cylindrical, and its
inner space accommodates the fuel pump and the pressure
regulator.
[0032] (Mode 4) The jet pump, fuel pump and pressure regulator are
assembled with the reservoir. In other words, the fuel pump,
pressure regulator and jet pump are all put into an assembly with
the reservoir in advance.
[0033] (Mode 5) The guide rails extending from the upper subunit
toward the lower subunit are formed integrally with the upper
subunit.
[0034] (Mode 6) The lower subunit is pressed against the bottom of
the fuel tank by the upper subunit with an elastic member.
[0035] (Mode 7) Each of the guide rails extending from the upper
subunit toward the lower subunit, is formed in a flat plate shape,
and has a long hole formed extending along a center line, in which
a large hole is formed to make both sides of it thinner so as to
form a frail portion.
[0036] (Mode 8) Each of the guide rails, which are formed in a flat
plate shape, has at its tip slits extending upward.
[0037] (Mode 9) Slots to accept the guide rails are integrally
molded with the reservoir.
[0038] (Mode 10) A tapered projection is provided in each of the
slots, and the guide rail is elastically deformed to ride over the
projection to engage the projection with the end of the long hole.
Once they are engaged, the projection is prohibited from severing
from the guide rail.
[0039] (Mode 11) A metal plate is arranged inside the slot.
[0040] (Mode 12) Snap fits protruding upward are integrally formed
with the bottom of the reservoir, and engaging holes are bored on
the circumference of the primary filter to engage with the snap
fits.
[0041] [Embodiments]
[0042] A reservoir unit according to a first preferred embodiment
of the present invention will now be described in detail with
reference to FIG. 1.
[0043] As shown in FIG. 1, a reservoir unit 2 of the embodiment
comprises an upper subunit 4 and a lower subunit 8, and installed
in a fuel tank 6 when it is used. The lower subunit 8 is provided
with a reservoir 20 in a cylindrical shape having a bottom (i.e.
shaped substantially like a glass), a primary filter 26, a fuel
pump 34, a pressure regulator 14 and a secondary filter 16. The
primary filter 26, the fuel pump 34, the pressure regulator 14 and
the secondary filter 16 are accommodated in the reservoir 20 to be
positioned, and constitute an assembly.
[0044] The primary filter 26, fuel pump 34, pressure regulator 14,
secondary filter 16, reservoir 20 and upper subunit 4 will be
described in detail below in this sequence.
[0045] The primary filter 26 is configured of a bag filter of
fine-texture nylon and a resin-built frame inserted into and
securing a certain volume within the bag. The inner space of the
bag filter is continuous to the suction port of the fuel pump 34.
The primary filter 26 is accommodated in the reservoir 20 and
arranged along the inner bottom of the reservoir 20. As shown in
FIGS. 4A and 4B, the frame is composed of a swelled portion 30
pressing a few parts of the bottom of the bag filter against the
inner bottom of the reservoir 20, and a frame body 29 keeping the
other parts of the bottom of the bag filter in a position slightly
away from the bottom of the reservoir 20. This arrangement serves
to secure spacing between the primary filter 26 and the inner
bottom of the reservoir 20 to enable the whole filtering face to
perform the filtering function.
[0046] On the circumference of the primary filter 26 are bored
engaging holes 26a to fit snap fits 31 protruding upward from the
inner bottom of the reservoir 20. Engagement of the engaging holes
26a with the snap fits 31 prevents the primary filter 26 from
floating away from the inner bottom of the reservoir 20, thereby
helping to keep it in a position along the inner bottom of the
reservoir 20.
[0047] The meshes of the bag filter of fine-texture nylon, when
exposed from the fuel, are clogged by the fuel as it surface
tension works. As long as even a small part of the bag filter is
soaked in the fuel, the fuel enters into the filter through the
soaked part of the bag, and accordingly the bag filter can still
absorb the fuel even if the remaining quantity of the fuel is so
small that the top of the bag filter is exposed. Any foreign matter
in the fuel is substantially removed by the primary filter 26, and
the remainder is further removed by the secondary filter 16 to be
elaborated upon afterwards. The fuel cleared of foreign matter by
the primary filter 26 is sucked by the fuel pump.
[0048] As shown in FIG. 1, the fuel pump 34 is formed in a
substantially vertical columnar shape, and has at its bottom a fuel
suction pipe (not shown). To the fuel suction pipe (not shown) is
connected the primary filter 26. At the top end of the fuel pump
34, there are provided an electrical connector 11 and a fuel
discharge pipe 12.
[0049] The fuel pump 34, driven by being supplied with electricity
through the electrical connector 11, sucks fuel in the reservoir 20
to be described afterwards from the primary filter 26, raises its
pressure, and discharges it from the fuel discharge pipe 12.
[0050] To the fuel discharge pipe 12 is connected the pressure
regulator 14. The pressure regulator 14 is a relief valve which,
when the pressure in the fuel discharge pipe 12 surpasses a
prescribed level, lets the fuel escape from the fuel discharge pipe
12 to keep the pressure within the fuel discharge pipe 12 at the
prescribed level. It maintains the pressure of the fuel to be fed
to the secondary filter 16, and eventually that of the fuel fed to
the internal combustion engine, at the prescribed level. The fuel
having escaped from the pressure regulator 14 is guided by piping
(not shown in FIG. 1) into a jet pump 40 to be described
afterwards. The pressure regulator 14 is accommodated in the
pressure regulator fitting part 19 of a filter cover 35 to be
elaborated upon afterwards, and is supported in a state of being
prevented from coming off by the assembling of its cap 13 into the
pressure regulator fitting part 19 of the filter cover 35.
[0051] Around the fuel pump 34 is formed a doughnut-shaped vessel
18, in which the secondary filter 16, also doughnut-shaped, is
accommodated and covered by the filter cover 35 which blocks the
top opening of the doughnut-shaped vessel 18. The doughnut-shaped
vessel 18 and the filter cover 35 are molded resin items. The
doughnut-shaped vessel 18 is bisected by the doughnut-shaped
secondary filter 16 into an inner chamber and an outer chamber, and
the fuel discharge pipe 12 leads to the outer chamber of the
doughnut-shaped vessel 18. To the inner chamber of the
doughnut-shaped vessel 18 leads a fuel feed pipe 36. The fuel
delivered from the fuel pump 34 passes the secondary filter 16 from
the outer chamber of the doughnut-shaped vessel 18 to reach the
inner chamber of the doughnut-shaped vessel 18 and enters the fuel
feed pipe 36. The fuel feed pipe 36 penetrates the upper subunit 4
and extends out of the fuel tank 6. In this embodiment according to
the invention, the fuel feed pipe 36 is connected to an injector
via a delivery pipe (neither shown), and supplies the injector with
fuel which is raised in pressure by the fuel pump 34, regulated by
the pressure regulator 14 to a constant pressure level, and cleared
of foreign matter by the primary filter 26 and the secondary filter
16. Into the hollow space within the doughnut-shaped vessel 18 is
inserted the fuel pump 34 from its bottom opening. Assembling of a
fitting stay 25 to the bottom of the doughnut-shaped vessel 18
results in supporting of the fuel pump 34 in a state in which the
pump is prevented from coming off. A cushion rubber 27 intervenes
between the fuel pump 34 and the fitting stay 25 to elastically
support the fuel pump 34.
[0052] Next will be described the upper subunit 4 with reference to
FIG. 1 and FIGS. 5A and 5B. The upper subunit 4, which is a molded
resin item, is provided with a substantially round disk portion 4b
fixed to the top face 6a of the fuel tank 6 to block the opening of
the fuel tank 6, a cylindrical wall 4a protruding from the bottom
face of the disk portion 4b, and a pair of guide rails 10a and 10b
extending downwards from the cylindrical wall 4a. The cylindrical
wall 4a can be fit into the fitting holes 6c of the fuel tank 6. As
shown in FIG. 1, fitting of the upper subunit 4 to block the
fitting holes 6c of the fuel tank 6 results in arrangement and
positioning of the reservoir unit 2 in the fuel tank 6. The outer
circumference of the upper subunit 4 is mounted over the edges of
the fitting holes 6c of the fuel tank 6 via a seal gasket (not
shown), and fastened over the fitting holes 6c of the fuel tank 6
with bolts (not shown). This results in fixing of the upper subunit
4 to the fuel tank 6.
[0053] The upper subunit 4 has an electrical connector 9 provided
with terminals vertically penetrating the disk portion 4b. To the
electrical connector 9 of the upper subunit 4 is electrically
connected an electrical connector 11 of the fuel pump 34 on the
lower side of the upper subunit 4. The electrical connector 9 of
the upper subunit 4 is also electrically connected on the top side
of the upper subunit 4 to a connector for power feed (not
shown).
[0054] As well illustrated in FIGS. 5A and 5B, the pair of guide
rails 10a and 10b extend from the cylindrical wall 4a of the upper
subunit 4. Each of the guide rails 10a and 10b is formed in a flat
plate shape. A long hole 108 is formed along the center line of
each of the guide rails 10a and 10b. At the top end of the long
hole 108 is formed a large hole 102, and the two sides of the large
hole 102 constitute a frail portion 104. At the tip of each of the
guide rails 10a and 10b are formed slits 106 extending upwards from
the lower end. The slits 106 are formed on both sides of the long
hole 108.
[0055] As well illustrated in FIG. 6, the reservoir 20 has
sheath-shaped slots 20a and 20b to accept the pair of guide rails
10a and 10b, and moves toward or away from the upper subunit 4
along the pair of guide rails 10a and 10b. Within the sheath-shaped
slots 20a and 20b are provided tapered projections 21a and 21b on
which the guide rails 10a and 10b are slidable in only one
direction. When the upper subunit 4 and the lower subunit 8 are
assembled, the guide rails 10a and 10b are elastically deformed to
ride over the tapered projections 21a and 21b. During normal use,
the tapered projections 21a and 21b are engaged with the ends of
the long holes 108 of the guide rails 10a and 10b so that the upper
subunit 4 and the lower subunit 8 may not sever from each
other.
[0056] Inside the sheath-shaped slots 20a and 20b to accept the
guide rails 10a and 10b are arranged metal plates 202. They can
prevent, when the guide rails 10a and 10b and the slots 20a and 20b
on the reservoir side to accept them slide relative to each other,
squeaking noise or the like from arising. There is no particular
limitation to the material of the metal plates 202, but stainless
steel, which is resistant to corrosion, has been selected for this
embodiment of the invention.
[0057] Between the upper subunit 4 and the lower subunit 8 is
provided a compression spring 7 (not shown in FIG. 1) as the
elastic member, and the spring 7 presses the lower subunit 8 toward
the bottom 6b of the fuel tank 6. The fuel tank 6 is blow-molded of
resin, and is subject to deformation by a change in the quantity of
remaining fuel and/or a change in atmospheric temperature.
Therefore, the lower subunit 8 is pressed all the time toward the
bottom 6b of the fuel tank 6 regardless of the deformation of the
fuel tank 6.
[0058] When a vehement acceleration works on the fuel tank 6, the
reservoir unit 2 tends to be displaced relative to the fuel tank 6.
If the guide rails 10a and 10b are firm then, the disk portion 4b
of the upper subunit 4 may be destroyed when the reservoir unit 2
is displaced relative to the fuel tank 6. The disk portion 4b of
the upper subunit 4 is especially subject to destruction at the
roots of the guide rails 10a and 10b. When the disk portion 4b is
destroyed, the fuel may escape from the fuel tank 6. In the
embodiment, as the frail portion 104 is formed in the guide rails
10a and 10b, even if a vehement acceleration works on the fuel tank
6 and the reservoir unit 2 is displaced relative to the fuel tank
6, the frail portion 104 will be destroyed first, and therefore the
disk portion 4b will not be. As there is the frail portion 104, it
can prevent the disk portion 4b from being damaged, so as to leak
the fuel. To add, even if the frail portion 104 is destroyed, the
fuel pump can continue to work because electric cables to drive the
fuel pump and the hose to feed fuel remain connected. Thus it is
possible to continue to feed fuel to the engine, and thereby
enabling the motor vehicle to run as required for ensuring
safety.
[0059] FIG. 2A shows a plan view of the reservoir 20, wherein the
positions of the snap fits 31 are altered from those shown in FIGS.
4A and 4B. Two snap fits 31 are sufficient to keep the primary
filter 26 arranged along the bottom of the reservoir 20.
[0060] FIG. 2B shows a sectional view of the jet pump 40 taken
along the center line (a line IIB-IIB) shown in FIG. 2A. In the
bottom of the reservoir 20, which is composed of a molded item of
resin, is formed a concave 42 to accept a jet pump body 41 of the
jet pump 40, and openings 44 and 46 communicating to the concave
are formed, penetrating the wall of the reservoir 20. The opening
44 is fitted with a hose to connect the pressure regulator 14 and
the opening 44, so that returning fuel from the pressure regulator
14 can be guided to the opening 44. The opening 46 opens into the
gap between the bottom of the reservoir 20 and the bottom 6b of the
fuel tank 6. As shown in FIG. 1, a slight spacing is secured
between the bottom of the reservoir 20 and the bottom 6b of the
fuel tank 6 by projections 28.
[0061] The jet pump body 41 is accommodated in the concave 42, and
the subsequent fixing of a plug 38 to the reservoir 20 causes the
jet pump body 41 to be fixed to the reservoir 20. The jet pump body
41 is provided with an opening 48 to accept returning fuel from the
pressure regulator 14, a passage 50 for accepting fuel from outside
the reservoir 20, and a venturi tube 52. When the jet pump body 41
is fixed to the reservoir 20, the opening 44 becomes continuous to
the opening 48, and the opening 46, to the passage 50.
[0062] As returning fuel from the pressure regulator 14 is guided
to the opening 44, that fuel passes through the venturi tube 52 of
the jet pump 40 as indicated by arrow A. As the flow rate of
returning fuel jetting out of the venturi tube 52 is fast, a
negative pressure is generated in the downstream part of the
venturi tube 52. This negative pressure causes, as indicated by
arrow B, fuel outside the reservoir 20 to pass through the opening
46 and the passage 50 to be sucked by the jet pump 40 and
discharged out of its discharge port 54.
[0063] From the discharge port 54 of the jet pump 40 are discharged
returning fuel from the pressure regulator 14 and fuel sucked from
outside the reservoir 20. Utilizing the flow velocity of returning
fuel from the pressure regulator 14, the jet pump 40 introduces
fuel outside the reservoir 20 into the reservoir 20.
[0064] The fuel discharged from the discharge port 54 of the jet
pump 40 contains many bubbles. When it is powerfully discharged
into the reservoir 20, the inner space of the reservoir may be
filled with fuel containing many bubbles. If the reservoir 20 is
filled with fuel containing bubbles, the fuel pump 34 may take in
many bubbles and become vapor-locked, or the fuel containing
bubbles may be supplied to the injector to disable the injector to
inject the intended quantity of fuel.
[0065] In this embodiment according to the invention, in order to
prevent the reservoir 20 from being filled with fuel containing
bubbles, a wall 24 fully surrounding the discharge port 54 of the
jet pump 40 is molded integrally with the resin-built reservoir 20.
Thus, the flow delivered from the jet pump 40 is discharged into
the closed space surrounded by the full-circle wall 24, the fuel in
that closed space is cleared of the bubbles, and the fuel is moved
outside the wall 24 after it is cleared of the bubbles, thereby
preventing the presence of many bubbles in the fuel within the
reservoir 20 outside the wall 24.
[0066] As shown in FIG. 2A, the wall 24 fully surrounds the
discharge port 54 of the jet pump 40. Its height is less than that
of the side wall of the reservoir 20. There is no particular
limitation to the shape of the wall 24, but it preferably should
have no corner in its planar view, i.e., be substantially oval or
substantially circular, shaped like a bean, because any corner
might invite concentration of bubbles in the fuel in that
corner.
[0067] A partition wall 22 is formed at a central part in the
full-circle wall 24, so configured that fuel delivered from the jet
pump 40 flow round the partition wall 22. The fuel delivered from
the jet pump 40 is discharged along the partition wall 22.
[0068] Clearances 56 and 58 are secured between the two sides of
the partition wall 22 and the full-circle wall 24. The clearance 56
can be formed by notching a part of the wall 22 as shown in FIG.
3A. It is sufficient for the clearance 56 to permit the delivered
flow to turn round the partition wall 22 a plurality of times, any
of the hole-shaped clearance 56b shown in FIG. 3B, a meshed
clearance 56c as shown in FIG. 3C or the like may be applied as
appropriate.
[0069] In this embodiment according to the invention, bubbles are
removed in the following manner.
[0070] (1) The fuel containing bubbles delivered from the discharge
port 54 of the jet pump 40 is not directly discharged into the
reservoir 20, but it goes into and fill the reservoir 20 only after
it hits the wall 24 and is thereby slowed in flow rate. For this
reason, the flow rate of the fuel in the reservoir 20 is slow, and
bubbles contained in the fuel float so as to prevent many of them
from being sucked by the fuel pump 34.
[0071] (2) When the fuel from the discharge port 54 of the jet pump
40 hits the wall 24, the removal of bubbles is accelerated.
[0072] (3) The fuel from the discharge port 54 of the jet pump 40
flows guided by the partition wall 22 and, when it sharply changes
its direction in something like a U-turn at the end of the wall,
the removal of bubbles is accelerated.
[0073] (4) As the fuel from the discharge port 54 of the jet pump
40 flows guided by the partition wall 22 and while it turns round
the partition wall 22 a plurality of times, the removal of bubbles
is accelerated.
[0074] The configuration of the walls 22 and 24 shown in FIG. 2A
provides all the four of the above-described effects, resulting in
virtually complete removal of bubbles.
[0075] When the quantity of bubbles contained in the fuel delivered
from the jet pump 40 is small, the above-described anti-bubble
measures need not be fully implemented.
[0076] In that case, for instance, the clearance 56 of the
partition wall 22 on the jet pump side can be dispensed with as in
the second preferred embodiment according to the invention, shown
in FIG. 7.
[0077] Or, the partition wall 22 itself may be unnecessary as in
the third preferred embodiment according to the invention, shown in
FIG. 8.
[0078] Further, the wall which the injected flow hits against need
not fully encircle the discharge port, but may only serve the
purpose of letting the flow hit against as in the fourth preferred
embodiment according to the invention, shown in FIG. 9. In this
case, it is preferable for this wall 24 to be concavely shaped
relative to the delivered flow in its planar view, because this
shape would contribute to increasing the ratio of bubbles being
caught.
[0079] Incidentally, although the fuel tank in the above
embodiments is made of resin, the tank may be made of the
conventional material.
[0080] While the invention has been described with reference to
preferred embodiments thereof, they are presented as mere examples,
but nothing to limit the scope of claims for the patent. Various
modifications and alterations of the specific embodiments described
above can be included within the spirit and scope of the following
claims.
[0081] Further, the technical elements described in this
specification or illustrated in the accompanying drawings can prove
technically useful either by themselves or in various combinations,
but not limited to the combinations in the claims contained in the
application. The aspects of the art described in this specification
or illustrated in the accompanying drawings achieve a plurality of
objects at the same time, and achieving any one of those objects
can be technically useful in itself.
[0082] In the reservoir unit according to the invention, as it has
a wall against which a fuel flow delivered from the jet pump hits,
fuel containing bubbles does not fill its reservoir, and
accordingly it can prevent the fuel pump from sucking a large
quantity of bubbles.
[0083] Further, in the invention, the bubble eliminating effect is
particularly significant when the wall against which the fuel flow
delivered from the jet pump hits surrounds the discharge port in a
full circle. Further, the wall fully surrounding the discharge port
serves as a breakwater against the leaking outside the reservoir of
the fuel in the reservoir when the fuel in the reservoir flows back
through the jet pump, and thereby prevents the fuel near the
suction port of the fuel pump from going out of the reservoir. As a
result, even when the fuel pump remains out of operation for a long
time with only a small quantity of fuel remaining in it, the fuel
feed can be smoothly resumed.
[0084] Further, providing a partition wall at the central part in
the full-circle wall in the above-described configuration would
provide a whirling stream and result in even more efficient removal
of bubbles.
[0085] By securing clearances on both sides of the partition wall
in the configuration according to the invention, a stream turning
round the partition wall a plurality of times can be obtained,
resulting in virtually complete elimination of bubbles having
introduced into the fuel.
* * * * *